Abstract: An improved method of constructing residential buildings incorporates a utility core or compartment, the outer walls of which are common to selected rooms of the building. The water, sewer, and gas piping systems are located in the utility core, and may be connected to fixtures within the building by appropriate piping and conduit extending directly through the common walls, rather than built into the walls through the foundation or through the floor of the building. The utility core may be formed to accommodate differing floor plans and is located to be accessible from the exterior of the building.